/*
 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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 */

package java.awt;

import java.beans.ConstructorProperties;

import java.lang.annotation.Native;

/**
 * The <code>BasicStroke</code> class defines a basic set of rendering
 * attributes for the outlines of graphics primitives, which are rendered
 * with a {@link Graphics2D} object that has its Stroke attribute set to
 * this <code>BasicStroke</code>.
 * The rendering attributes defined by <code>BasicStroke</code> describe
 * the shape of the mark made by a pen drawn along the outline of a
 * {@link Shape} and the decorations applied at the ends and joins of
 * path segments of the <code>Shape</code>.
 * These rendering attributes include:
 * <dl>
 * <dt><i>width</i>
 * <dd>The pen width, measured perpendicularly to the pen trajectory.
 * <dt><i>end caps</i>
 * <dd>The decoration applied to the ends of unclosed subpaths and
 * dash segments.  Subpaths that start and end on the same point are
 * still considered unclosed if they do not have a CLOSE segment.
 * See {@link java.awt.geom.PathIterator#SEG_CLOSE SEG_CLOSE}
 * for more information on the CLOSE segment.
 * The three different decorations are: {@link #CAP_BUTT},
 * {@link #CAP_ROUND}, and {@link #CAP_SQUARE}.
 * <dt><i>line joins</i>
 * <dd>The decoration applied at the intersection of two path segments
 * and at the intersection of the endpoints of a subpath that is closed
 * using {@link java.awt.geom.PathIterator#SEG_CLOSE SEG_CLOSE}.
 * The three different decorations are: {@link #JOIN_BEVEL},
 * {@link #JOIN_MITER}, and {@link #JOIN_ROUND}.
 * <dt><i>miter limit</i>
 * <dd>The limit to trim a line join that has a JOIN_MITER decoration.
 * A line join is trimmed when the ratio of miter length to stroke
 * width is greater than the miterlimit value.  The miter length is
 * the diagonal length of the miter, which is the distance between
 * the inside corner and the outside corner of the intersection.
 * The smaller the angle formed by two line segments, the longer
 * the miter length and the sharper the angle of intersection.  The
 * default miterlimit value of 10.0f causes all angles less than
 * 11 degrees to be trimmed.  Trimming miters converts
 * the decoration of the line join to bevel.
 * <dt><i>dash attributes</i>
 * <dd>The definition of how to make a dash pattern by alternating
 * between opaque and transparent sections.
 * </dl>
 * All attributes that specify measurements and distances controlling
 * the shape of the returned outline are measured in the same
 * coordinate system as the original unstroked <code>Shape</code>
 * argument.  When a <code>Graphics2D</code> object uses a
 * <code>Stroke</code> object to redefine a path during the execution
 * of one of its <code>draw</code> methods, the geometry is supplied
 * in its original form before the <code>Graphics2D</code> transform
 * attribute is applied.  Therefore, attributes such as the pen width
 * are interpreted in the user space coordinate system of the
 * <code>Graphics2D</code> object and are subject to the scaling and
 * shearing effects of the user-space-to-device-space transform in that
 * particular <code>Graphics2D</code>.
 * For example, the width of a rendered shape's outline is determined
 * not only by the width attribute of this <code>BasicStroke</code>,
 * but also by the transform attribute of the
 * <code>Graphics2D</code> object.  Consider this code:
 * <blockquote><tt>
 * // sets the Graphics2D object's Transform attribute
 * g2d.scale(10, 10);
 * // sets the Graphics2D object's Stroke attribute
 * g2d.setStroke(new BasicStroke(1.5f));
 * </tt></blockquote>
 * Assuming there are no other scaling transforms added to the
 * <code>Graphics2D</code> object, the resulting line
 * will be approximately 15 pixels wide.
 * As the example code demonstrates, a floating-point line
 * offers better precision, especially when large transforms are
 * used with a <code>Graphics2D</code> object.
 * When a line is diagonal, the exact width depends on how the
 * rendering pipeline chooses which pixels to fill as it traces the
 * theoretical widened outline.  The choice of which pixels to turn
 * on is affected by the antialiasing attribute because the
 * antialiasing rendering pipeline can choose to color
 * partially-covered pixels.
 * <p>
 * For more information on the user space coordinate system and the
 * rendering process, see the <code>Graphics2D</code> class comments.
 *
 * @author Jim Graham
 * @see Graphics2D
 */
public class BasicStroke implements Stroke {

  /**
   * Joins path segments by extending their outside edges until
   * they meet.
   */
  @Native
  public final static int JOIN_MITER = 0;

  /**
   * Joins path segments by rounding off the corner at a radius
   * of half the line width.
   */
  @Native
  public final static int JOIN_ROUND = 1;

  /**
   * Joins path segments by connecting the outer corners of their
   * wide outlines with a straight segment.
   */
  @Native
  public final static int JOIN_BEVEL = 2;

  /**
   * Ends unclosed subpaths and dash segments with no added
   * decoration.
   */
  @Native
  public final static int CAP_BUTT = 0;

  /**
   * Ends unclosed subpaths and dash segments with a round
   * decoration that has a radius equal to half of the width
   * of the pen.
   */
  @Native
  public final static int CAP_ROUND = 1;

  /**
   * Ends unclosed subpaths and dash segments with a square
   * projection that extends beyond the end of the segment
   * to a distance equal to half of the line width.
   */
  @Native
  public final static int CAP_SQUARE = 2;

  float width;

  int join;
  int cap;
  float miterlimit;

  float dash[];
  float dash_phase;

  /**
   * Constructs a new <code>BasicStroke</code> with the specified
   * attributes.
   *
   * @param width the width of this <code>BasicStroke</code>.  The width must be greater than or
   * equal to 0.0f.  If width is set to 0.0f, the stroke is rendered as the thinnest possible line
   * for the target device and the antialias hint setting.
   * @param cap the decoration of the ends of a <code>BasicStroke</code>
   * @param join the decoration applied where path segments meet
   * @param miterlimit the limit to trim the miter join.  The miterlimit must be greater than or
   * equal to 1.0f.
   * @param dash the array representing the dashing pattern
   * @param dash_phase the offset to start the dashing pattern
   * @throws IllegalArgumentException if <code>width</code> is negative
   * @throws IllegalArgumentException if <code>cap</code> is not either CAP_BUTT, CAP_ROUND or
   * CAP_SQUARE
   * @throws IllegalArgumentException if <code>miterlimit</code> is less than 1 and
   * <code>join</code> is JOIN_MITER
   * @throws IllegalArgumentException if <code>join</code> is not either JOIN_ROUND, JOIN_BEVEL, or
   * JOIN_MITER
   * @throws IllegalArgumentException if <code>dash_phase</code> is negative and <code>dash</code>
   * is not <code>null</code>
   * @throws IllegalArgumentException if the length of <code>dash</code> is zero
   * @throws IllegalArgumentException if dash lengths are all zero.
   */
  @ConstructorProperties({"lineWidth", "endCap", "lineJoin", "miterLimit", "dashArray",
      "dashPhase"})
  public BasicStroke(float width, int cap, int join, float miterlimit,
      float dash[], float dash_phase) {
    if (width < 0.0f) {
      throw new IllegalArgumentException("negative width");
    }
    if (cap != CAP_BUTT && cap != CAP_ROUND && cap != CAP_SQUARE) {
      throw new IllegalArgumentException("illegal end cap value");
    }
    if (join == JOIN_MITER) {
      if (miterlimit < 1.0f) {
        throw new IllegalArgumentException("miter limit < 1");
      }
    } else if (join != JOIN_ROUND && join != JOIN_BEVEL) {
      throw new IllegalArgumentException("illegal line join value");
    }
    if (dash != null) {
      if (dash_phase < 0.0f) {
        throw new IllegalArgumentException("negative dash phase");
      }
      boolean allzero = true;
      for (int i = 0; i < dash.length; i++) {
        float d = dash[i];
        if (d > 0.0) {
          allzero = false;
        } else if (d < 0.0) {
          throw new IllegalArgumentException("negative dash length");
        }
      }
      if (allzero) {
        throw new IllegalArgumentException("dash lengths all zero");
      }
    }
    this.width = width;
    this.cap = cap;
    this.join = join;
    this.miterlimit = miterlimit;
    if (dash != null) {
      this.dash = (float[]) dash.clone();
    }
    this.dash_phase = dash_phase;
  }

  /**
   * Constructs a solid <code>BasicStroke</code> with the specified
   * attributes.
   *
   * @param width the width of the <code>BasicStroke</code>
   * @param cap the decoration of the ends of a <code>BasicStroke</code>
   * @param join the decoration applied where path segments meet
   * @param miterlimit the limit to trim the miter join
   * @throws IllegalArgumentException if <code>width</code> is negative
   * @throws IllegalArgumentException if <code>cap</code> is not either CAP_BUTT, CAP_ROUND or
   * CAP_SQUARE
   * @throws IllegalArgumentException if <code>miterlimit</code> is less than 1 and
   * <code>join</code> is JOIN_MITER
   * @throws IllegalArgumentException if <code>join</code> is not either JOIN_ROUND, JOIN_BEVEL, or
   * JOIN_MITER
   */
  public BasicStroke(float width, int cap, int join, float miterlimit) {
    this(width, cap, join, miterlimit, null, 0.0f);
  }

  /**
   * Constructs a solid <code>BasicStroke</code> with the specified
   * attributes.  The <code>miterlimit</code> parameter is
   * unnecessary in cases where the default is allowable or the
   * line joins are not specified as JOIN_MITER.
   *
   * @param width the width of the <code>BasicStroke</code>
   * @param cap the decoration of the ends of a <code>BasicStroke</code>
   * @param join the decoration applied where path segments meet
   * @throws IllegalArgumentException if <code>width</code> is negative
   * @throws IllegalArgumentException if <code>cap</code> is not either CAP_BUTT, CAP_ROUND or
   * CAP_SQUARE
   * @throws IllegalArgumentException if <code>join</code> is not either JOIN_ROUND, JOIN_BEVEL, or
   * JOIN_MITER
   */
  public BasicStroke(float width, int cap, int join) {
    this(width, cap, join, 10.0f, null, 0.0f);
  }

  /**
   * Constructs a solid <code>BasicStroke</code> with the specified
   * line width and with default values for the cap and join
   * styles.
   *
   * @param width the width of the <code>BasicStroke</code>
   * @throws IllegalArgumentException if <code>width</code> is negative
   */
  public BasicStroke(float width) {
    this(width, CAP_SQUARE, JOIN_MITER, 10.0f, null, 0.0f);
  }

  /**
   * Constructs a new <code>BasicStroke</code> with defaults for all
   * attributes.
   * The default attributes are a solid line of width 1.0, CAP_SQUARE,
   * JOIN_MITER, a miter limit of 10.0.
   */
  public BasicStroke() {
    this(1.0f, CAP_SQUARE, JOIN_MITER, 10.0f, null, 0.0f);
  }


  /**
   * Returns a <code>Shape</code> whose interior defines the
   * stroked outline of a specified <code>Shape</code>.
   *
   * @param s the <code>Shape</code> boundary be stroked
   * @return the <code>Shape</code> of the stroked outline.
   */
  public Shape createStrokedShape(Shape s) {
    sun.java2d.pipe.RenderingEngine re =
        sun.java2d.pipe.RenderingEngine.getInstance();
    return re.createStrokedShape(s, width, cap, join, miterlimit,
        dash, dash_phase);
  }

  /**
   * Returns the line width.  Line width is represented in user space,
   * which is the default-coordinate space used by Java 2D.  See the
   * <code>Graphics2D</code> class comments for more information on
   * the user space coordinate system.
   *
   * @return the line width of this <code>BasicStroke</code>.
   * @see Graphics2D
   */
  public float getLineWidth() {
    return width;
  }

  /**
   * Returns the end cap style.
   *
   * @return the end cap style of this <code>BasicStroke</code> as one of the static
   * <code>int</code> values that define possible end cap styles.
   */
  public int getEndCap() {
    return cap;
  }

  /**
   * Returns the line join style.
   *
   * @return the line join style of the <code>BasicStroke</code> as one of the static
   * <code>int</code> values that define possible line join styles.
   */
  public int getLineJoin() {
    return join;
  }

  /**
   * Returns the limit of miter joins.
   *
   * @return the limit of miter joins of the <code>BasicStroke</code>.
   */
  public float getMiterLimit() {
    return miterlimit;
  }

  /**
   * Returns the array representing the lengths of the dash segments.
   * Alternate entries in the array represent the user space lengths
   * of the opaque and transparent segments of the dashes.
   * As the pen moves along the outline of the <code>Shape</code>
   * to be stroked, the user space
   * distance that the pen travels is accumulated.  The distance
   * value is used to index into the dash array.
   * The pen is opaque when its current cumulative distance maps
   * to an even element of the dash array and transparent otherwise.
   *
   * @return the dash array.
   */
  public float[] getDashArray() {
    if (dash == null) {
      return null;
    }

    return (float[]) dash.clone();
  }

  /**
   * Returns the current dash phase.
   * The dash phase is a distance specified in user coordinates that
   * represents an offset into the dashing pattern. In other words, the dash
   * phase defines the point in the dashing pattern that will correspond to
   * the beginning of the stroke.
   *
   * @return the dash phase as a <code>float</code> value.
   */
  public float getDashPhase() {
    return dash_phase;
  }

  /**
   * Returns the hashcode for this stroke.
   *
   * @return a hash code for this stroke.
   */
  public int hashCode() {
    int hash = Float.floatToIntBits(width);
    hash = hash * 31 + join;
    hash = hash * 31 + cap;
    hash = hash * 31 + Float.floatToIntBits(miterlimit);
    if (dash != null) {
      hash = hash * 31 + Float.floatToIntBits(dash_phase);
      for (int i = 0; i < dash.length; i++) {
        hash = hash * 31 + Float.floatToIntBits(dash[i]);
      }
    }
    return hash;
  }

  /**
   * Returns true if this BasicStroke represents the same
   * stroking operation as the given argument.
   */
  /**
   * Tests if a specified object is equal to this <code>BasicStroke</code>
   * by first testing if it is a <code>BasicStroke</code> and then comparing
   * its width, join, cap, miter limit, dash, and dash phase attributes with
   * those of this <code>BasicStroke</code>.
   *
   * @param obj the specified object to compare to this <code>BasicStroke</code>
   * @return <code>true</code> if the width, join, cap, miter limit, dash, and dash phase are the
   * same for both objects; <code>false</code> otherwise.
   */
  public boolean equals(Object obj) {
    if (!(obj instanceof BasicStroke)) {
      return false;
    }

    BasicStroke bs = (BasicStroke) obj;
    if (width != bs.width) {
      return false;
    }

    if (join != bs.join) {
      return false;
    }

    if (cap != bs.cap) {
      return false;
    }

    if (miterlimit != bs.miterlimit) {
      return false;
    }

    if (dash != null) {
      if (dash_phase != bs.dash_phase) {
        return false;
      }

      if (!java.util.Arrays.equals(dash, bs.dash)) {
        return false;
      }
    } else if (bs.dash != null) {
      return false;
    }

    return true;
  }
}
